Integrated evaluation of stiffness degradation by combining Resonant-Column, Cyclic Triaxial and Cyclic Simple Shear Tests: Application to Riotinto mine tailings

Abstract

This study introduces a methodology for integrating stiffness degradation curve results obtained through various experimental methods. The proposed approach involves an extensive experiment program comprising 108 resonant column tests, 27 cyclic simple shear tests, and 29 cyclic triaxial tests. These tests were conducted under diverse cyclic strain and effective consolidation stress conditions, focusing on identifying variables to unify the behaviour for each material type into a common predictive equation. To validate this novel approach, three materials derived from the tailings of the Riotinto mines (Huelva, Spain) were tested. The methodology provides a detailed account of testing procedures for integrating the test results from the three devices. Laboratory findings indicate that capturing the variation trend of soil stiffness degradation regarding cyclic strain and effective consolidation stress is feasible. This is achieved using empirical functions, such as exponential and potential equations based on the strain range. The methodology enables the determination of necessary adjustment constants specific to the material tested, which can be obtained through the developed approach, contributing to preserving tailings storage facilities located in zones under seismic risk.